ASSESSMENT OF VARIATIONS IN CATHARANTHUS ROSEUS L. INDUCED BY GAMMA RAYS AND SODIUM AZIDE USING RAPD MARKERS

Abstract

The study of genetic variations in Catharanthus roseus L. induced by gamma rays and sodium azide using RAPD markers transpired in 2021–2022 at the Department of Biology, University of Kufa, Iraq. The seeds of two cultivars of Catharanthus roseus L., i.e., victory pure white and local (pink variety), received two doses of gamma rays (50 and 75 Gray) and four sodium azide concentrations (0.2%, 0.4%, 0.6%, and 0.8%). Non-treated seeds of both cultivars also served as a control for comparison. Evaluating the effects obtained through the exposure of C. roseus seeds to gamma rays and sodium azide employed DNA markers, including 16 primers used in applying RAPDs. DNA extraction, accomplished from fresh apical leaves, underwent molecular markers application. RAPD markers could detect the generation of genetic variation induced by gamma rays and sodium azide treatments through the appearance of polymorphic bands. Using 16 RAPD primers, the largest molecular size was 2,543 bp produced by primer OPB-17, with the lowest 114 bp produced by primer OPC-08. The highest number of main and polymorphic bands was 18 and 10, respectively, in primer OPA-10. The highest number of monomorphic bands was eight in primer OPX-17, which affected its ability to give the lowest value for polymorphism. The highest number of amplified bands was 78 bands in primer OPC-09. Primer OPA-10 provided the highest number of polymorphic and unique bands, as well as, the highest values for discrimination and primer efficiency. Primer OPC-09, with seven treatments resulting in a unique fingerprint, is superior to all other primers.